Unfortunately, the Covenant then jam the Human communications network along with the rest of the base, shutting off the power. Truth appears on the main view screen, telling the Humans that their world will burn. The base is then attacked by a large contingent of Covenant troops. The Master Chief first clears the south hangar, allowing the UNSC personnel to evacuate. Unable to fight off the invaders, Keyes orders a bomb placed in the operations center. Meanwhile, Jiralhanae capture the barracks and take many Marines prisoner. The Chief and the Arbiter retake the barracks and rescue as many Marines as they can. They then bring the survivors up to the landing pad where Keyes is waiting with a Pelican. After fighting off another group of Jiralhanae, they meet up with Johnson who informs them that Jiralhanae have seized the Ops Center and disarmed the bomb. Keyes orders the Chief to retake the Ops Centers while the others evacuate. The Chief clears out the Covenant inside the Ops Center and rearms the bomb. He then makes his way back to the south hangar, where he finds a service elevator. Moments later, the bomb detonates, sending the elevator into free fall and causing the Chief to black out.

Commander Keyes: "We stopped it, but only temporarily. Now, the Prophet of Truth is looking for something called 'The Ark', where he'll be able to fire all the Halo Rings. If he succeeds, Humanity, the Covenant, every sentient being in the Galaxy..."

Lord Hood (Video COM): "Glad to hear it. The Commander's come up with a good plan. But without you, I wasn't sure we could pull it off."

Commander Keyes: "Truth's ships are clustered above the excavation site. And his infantry has deployed Anti-Aircraft Batteries around the perimeter. But, if we neutralize one of the batteries, punch a hole in Truth's defenses..."

Lord Hood (Video COM): "I'll initiate a low-level strike. Hit 'em right where it hurts. I only have a handful of ships, Master Chief. It's a big risk. But I'm confident—"

Prophet of Truth (Video COM): "You are, all of you, vermin. Cowering in the dirt, thinking what, I wonder? That you might escape the coming fire? No. Your world will burn until its surface is but glass! And not even your Demon will live to creep, blackened from its hole to mar the reflection of our passage... the culmination of our Journey. For your destruction is the will of the gods! And I? I am their instrument!"

Marine: "Those Brutes secure the hangar, we won't be able to get our birds out."

The Marines find the vehicle access. A Warthog is in battle with many Covenant soldiers. Unggoy lob plasma grenades and destroy it. The Chief and accompanying Marines engage and defeat the Covenant. A Jiralhanae wielding a brute shot enters the vehicle access with a group of Unggoy. The team eliminate the Covenant troops and push onward. They go through the open door and defeat the Covenant there, which consists of many Unggoy and Kig-Yar Snipers. Proceeding, the Chief and Marines reach the hangar.

Marine #10: "Wipe those bastards off the deck!"

Marine #11: "Pelicans can't launch until the hangar's clear!"

The Chief and Marines go on the offense and secure the deck. Multiple Phantom dropships enter the hangar, delivering groups of infantry in an effort to re-take the stategically important room. From a distance, Hornets and Banshees are seen engaged in an aerial fight near a Cruiser which keeps sending Covenant reinforcements to the base. The Chief and Marines make use of several turrets and defend the hangar. The UNSC forces eventually prevail and the Phantoms retreat.

The Pelican hanging on a crane in one of the docks slides out and is released. The Dropship lands to evac the Marines in the hangar, while the Master Chief restocks on weapons and ammo.

The Chief heads back to the Ops Center. Marines pass by for evac. Back in the vehicle access, two Marines, staying behind until the next evac, hear a loud banging as well as the sound of insectoid wings beating in the ventilation pipes as something makes its way through.

Commander Keyes (Loudspeaker): "Anyone in the barracks, I need a sit-rep. Now!"

The Master Chief meets with the Marines in the cave, defending the Ops Center.

Marine #8: "Sir, this way."

A single Yanme'e suddenly appears above him and picks him up. (The Yanme'e can be killed before it picks up the Marine. If it does, he can still be saved by simply shooting the Yanme'e, which will drop the Marine).

Female Marine: "Look! Coming outta the vents!"

A massive swarm of Yanme'e starts pouring out the ventilation shafts, and engulfs the room.

The Master Chief meets with Johnson smoking a cigar and other defending Marines setting up an explosive device, but Thel 'Vadam isn't with them. (Single Player Only)

Gunnery Sergeant (Stacker or Reynolds): "If I try to hook up a timer, it might just go off by itself."

Commander Keyes (Video COM): "Johnson."

Sergeant Johnson: "Mm-hmm?"

Commander Keyes (Video COM): "You might wanna put that out."

Johnson drops his cigar and stamps on it.

Commander Keyes (Video COM): "Chief, have a look. A little going-away gift for the Covenant. We've linked it to smaller charges throughout the base. Johnson, soon as the evacuation is complete, start the timer."

Sergeant Johnson: "Understood."

Commander Keyes (Video COM): "Good luck, everyone. See you on the last Pelican out."

The feed disconnects.

Johnson: "Follow me, Chief."

(Co-op Change)Johnson: "Chief, Arbiter. Follow me."

Johnson leads the Chief to the back of the room, guarded by four Marines.

Sergeant Johnson: "Brutes have taken the barracks. Marines are trapped inside. Those apes ain't much for mercy, Chief. We both know what they do to prisoners."

The Master Chief takes weapons and ammo from a weapons locker.

Sergeant Johnson: "Get to the barracks, save those men. Then escort them to the Landing Pad for evac."

If the player stays near the bomb:

Sergeant Johnson: "I'll guard the bomb, Chief. Get yourself to the Barracks."

The Jiralhanae disperse, intent on tracking down the source. The Chief surprises them and manages to take several Jiralhanae out. Reinforcements soon enter from an open door near the Chieftain, many wielding Covenant carbines. Once most of his pack have been slain, the Chieftain brandishes his hammer and charges at the Chief, usually engaging an invincibility unit. Regardless, the Chief prevails and completely ousts the Jiralhanae pack.

The Master Chief continues on through a corridor, but it's caved in. Finding a hole in the floor, he jumps down into a shaft. At the bottom are several pipe entrances, which Yanme'e fly in and out of.

Master Chief jumps down through vertical shafts into a canal, where he finds Thel 'Vadam, fighting off a small group of Yanme'e. (Single Player Only)

ArbiterThel 'Vadam: "Half-wit insects! The Prophets use you like they used me! Reject their lies! Rebel, or all your hives will perish!"

After 'Vadam takes care of the Yanme'e, he and the Chief regroup.

Thel 'Vadam: "Spartan, the Brutes have taken your soldiers. As prisoners or meat for their bellies, I do not know. In case some yet live, let us be careful when we shoot."

The Master Chief and 'Vadam enter the barracks. They see a captive Marine thrown hard into a pillar, where multiple Marine corpses lie. The Marine dies and falls limply to the ground, and the Chief and 'Vadam rush in. One Marine being held by a Jiralhanae begs for mercy as it decides to kill him, too.

The Master Chief about to save the Marine prisoner.

Marine Prisoner: "No! Please!"

Jiralhanae: "Look, it has soiled itself! These are whelps, not warriors!"

The Chief can opt to attack the Jiralhanae, which releases the Marine prisoner.

If the player fails to save him, the Jiralhanae breaks his spine and throws him on the ground behind him, laughing.

If the player saves the Marine:

Marine Prisoner: "That was close, too close."

or

Marine Prisoner: "Close, too damn close."

Further down the corridor a Jiralhanae Captain holds a Marine by the ankle. Another marine is being held by the neck. Their survival depends on how fast the Chief is at attacking their captor(s). (On higher difficulties, the Jiralhanae are reinforced by Kig-yar infantry).

The Chief and 'Vadam kill the Jiralhanae and save the prisoners (optional). While the freed Marines rush for weapons, the Chief and 'Vadam move through the barracks, killing more Jiralhanae and freeing another group of prisoners.

After taking out the Brutes, the surviving Marines grab weapons from more piles of corpses, taking a second to grieve for their comrades while the Chief and 'Vadam resupply and reload. They continue their rescue throughout the barracks, defeating the remaining Jiralhanae, including a Jiralhanae War Chieftain with a detached plasma turret, and rescuing (a maximum of) seven Marines.

Kilo 23 takes off, getting out of the Jiralhanae's reach. Noticing the Chief and 'Vadam, the Jiralhanae Jumpers attack them. Reinforcements enter from above the observation room as well as from another door. The Chief, along with his allies ultimately defeat the Jiralhanae and secure the flight deck, a door at the road below opens. Johnson arrives, holding an SMG and leading a group of surviving Marines. The squad is under fire from a group of Yanme'e.

Sergeant Johnson: "Drones! Go! I'll cover you!"

The Chief and 'Vadam assist Johnson and his squad in killing the aliens. The few Yanme'e are quickly eliminated. Kilo 23 returns for final evac. The barracks survivors and Johnson's squad board the Pelican dropship.

Sergeant Johnson: "Brutes. In the Ops Center. They disarmed the bomb. Sorry, Commander, there were too many. Even for me."

Commander Keyes (COM): "Chief, get back to the Ops Center. Kill those Brutes. Rearm the bomb. I've gotta get these men out of here. But I'll radio with another exit. Good luck."

Johnson and Thel 'Vadam board the Pelican, and it takes off. The Master Chief goes along the road Johnson previously came from, passing by destroyed Warthogs and dead Marines. (In Co-op, 'Vadam will accompany the Chief.)

Cortana (Cortana Moment): "You will be the protectors of Earth and all her colonies."

The Chief walks on through to another roadway, with Covenant plasma cannons set up. Using the Plasma Cannons and/or using all available cover, he clears out a large contingent of Unggoy and Kig-Yar along with a pair of Kig-Yar Snipers. The Chief soon gets back to the Motor Pool next door to the Ops Center.

If the player is taking a while:

Sergeant Johnson (COM): "Chief, follow the service tunnel to the Motor Pool."

If the player still stalls:

Sergeant Johnson (COM): "Head through the Motor Pool to get to the Ops Center."

The Chief heads back up the corridor behind the Ops Center, and sneaks in. Inside, he witnesses a Jiralhanae War Chieftain communicating with the Prophet of Truth via the Ops Center communications. With the Chieftain are a several Unggoy and a pair of Jiralhanae Captains. (On higher difficulties, another Jiralhanae mans a plasma cannon at the far end of the room.)

If the Chief isn't spotted, he can spy on the conversation between Truth and the Chieftain.

Jiralhanae War Chieftain: "Success, Holy One! We have taken their Command Center!"

Truth (Video COM): "Have you discovered how they plan to stop me?"

Jiralhanae War Chieftain: (nervously) "Not just yet, Noble Prophet."

Truth (Video COM): "Find me what I need to know, or your place on the path is forfeit. Tell me you understand!"

Jiralhanae War Chieftain: "Yes, Holy One. It shall be done."

Truth disconnects from the screen.

Jiralhanae War Chieftain: (to his subordinates) "Have the Drones scour these machines! Find out what these heathens know about the Ark!"

As the Unggoy and Jiralhanae Captains get busy, the Chief takes them by surprise and defeats them. The War Chieftain opens fire on the Spartan with a fuel rod gun but the Chief manages to overcome him, taking back the Ops Center and the bomb.

If the player waits around a bit:

Sergeant Johnson (COM): "Hit the switch, Chief. Arm that bomb!"

The Master Chief reactivates the bomb and the alarm sounds.

Commander Keyes (COM): "That did it, Chief! Bomb's armed."

Sergeant Johnson (COM): "We got your exit. A service elevator in the hangar. Head downstairs, cut through the caves!"

The Chief heads back into the cave, where Unggoy run wildly. He then heads through the corridors.

Cortana (Cortana Moment): "There will be a great deal of hardship on the road ahead."

Sergeant Johnson (COM): "Get on the elevator, Chief! You're out of time!"

The Master Chief makes it to the service elevator, and activates it. The door doesn't fully shut. Something explodes and flames flicker through the gap.

Cortana (Cortana Moment): "This place will become your home."

The elevator descends. The Master Chief hears a massive boom. He looks up and sees the flames roar through the open door. The violent shaking disconnects the elevator and sends it plummeting down. It crashes and the Chief blacks out.

On this level, it is possible to find Gunnery Sergeant Stacker or Reynolds in three different places in a short amount of time, although they did not accompany the player throughout the base. They can be found holding position after killing the swarm of Drones outside the Ops Center, then operating the bomb, then being held prisoner in the barracks.

Occasionally, rats can be seen scurrying across the floor in some parts of the level. They appear on the player's Motion tracker as small yellow dots — friendlies. Players can kill them and even melee their dead bodies around. If the player turns against the Marines, the rats will be shown as red dots on the Motion tracker.

Players can get into the hangar where the Pelican picks up the remaining marines and takes off.

If one opens the door to the Motor Pool and doesn't go through, the door to Ops Center will remain open. The player can then lure the Brutes, and eventually the Chieftain, into the Ops Center by attacking them afar using the Battle Rifle. However, the Chieftain will not attack the Marines, and vice-versa. The player can even lure the Chieftain downstairs, though he will not chase the player into the large cave area.

There is a glitch that allows the player to get infinite weapons for the battle inside the Motor Pool.

There is a female Marine in the barracks that has white sleeves under her armor and a backpack, if ones shoots or melees her helmet, it will fly off but she will still have it on and cannot be taken off.

By dropping a Deployable Cover in the small stairway that Johnson and his Marines use to get to the landing pad, players can block off the stairway and Johnson and his Marines will cease to move, stopping Miranda Keyes's Pelican from taking off.

If you are playing Co-op on this level, the Arbiter has a melee animation even when he is unarmed. He will melee like a normal Elite. The melee attack does no damage. It is possible to disarm the AI Arbiter in single player by giving him a support weapon and getting him to ride in a vehicle or killing him and taking his weapon for a empty weapon. However, the AI controlled Arbiter's melee does damage. The same glitch can be performed if you use a glitch to allow an Elite character model to be unarmed in forge. Also, the Arbiter has a special grenade throw animation similar to the Halo: Combat Evolved Elites and Halo 3 level Floodgate Elites when he is unarmed. The grenade throw can be performed in multiplayer and Co-op if you are playing as a Elite character model. You don't necessarily have to be unarmed. You will need two weapons and grenades. Press the Y button to switch to your secondary weapon and quickly press the LT. If you did it correctly, you should have thrown a grenade like Floodgate Elites.

When playing as the Arbiter, N’tho ‘Sraom, or Usze ‘Taham, if you press the Y when you're unarmed at the beginning of the level, your player model will shuffle its feet. This can be seen only by the person who does it.

Many of the Marines are the same models with different voices in the opening cutscene, such as one of the injured men and a technician that speaks with the Commander. This is most likely for Bungie to save resources and not create multiple models for Marines.

After saving the Marines in the Barracks, CommanderKeyes will pilot a Pelican to evacuate them, if one looks closely, she is holding the controls of the Pelican like the controls of a Hornet.

Sergeant Johnson drops a cigar and steps on it when the player(s) first see the bomb. Upon closer examination, however, one can see that the cigar is still lit. In fact, it is completely unaffected by being stepped on.

If one manages to save every possible Marine being held captive in Barrack B, the evacuation Pelican will run out of seats leaving Thel 'Vadam with no other option but to sit in a seat already occupied by a Marine.

In Theater mode, when Miranda Keyes tells Master Chief about their farewell party to the Brutes, go upstairs next to the computer. It will say MAC and WAC and start playing the Halo theme song with beep sounds.

The Prophet of Truth's line, "...your destruction is the will of the gods. And I... I am their instrument!" is a rephrasing of the message sent to Battlegroup 4 during the First Battle of Harvest. Likewise, the line, "Your world will burn until its surface is but glass" is a restatement of a message sent to the surface of Biko in 2526.[4]

The "Seventh Column" icon appears in the opening cinematic. Immediately after Commander Keyes says "Give the order, we're closing shop," the screen cuts to a bearded marine who says "Ma'am?" The screen behind him reveals a map of the base, with the Seven Pillars icon appearing in the middle of the lower-right quadrant.

The men manning the computers at the beginning of the level are Naval personnel, which (aside from Crow's Nest) are only seen in-game in the Halo: Combat Evolvedcampaign levels The Pillar of Autumn and Halo.

The third section of this level (Last One Out, Get The Lights) could be a reference to the episode name of Season One finale of Red vs Blue (Last One Out, Hit The Lights).

When the Drones attack, Sgt. Stacker/Reynolds will say "Take 'em down - short, controlled bursts!" This may be a reference to Aliens, as the Halo series has had many Aliens references, and possibly because the Drones and the Xenomorphs share more similarities more than any Covenant species.

On the boxes in the part of the room farthest from the monitors is the number 2401, the number of Installation 05's Monitor, and a factor of 7. Similarly, in the first hangar, there is a generator under the floor marked with the EMG 2401 logo, likely in reference to said Monitor.

There are a total of seven Marines players can save in the Barracks.

On some of the screens at the Ops-Center there is a blue screen titled WAC which the screen is a reference to Microsoft's infamous Blue Screen of Death.

At the end of the level, a large explosion manages to shoot out of the opening in the elevator's blast doors before it completely closes. This could be a reference to near the ending of the The Maw from Combat Evolved in which a near identical occurrence takes place when John enters the service elevator in order to flee from the destruction of the Pillar of Autumn.

The Banshees and Hornets outside the hangar aren't real. They lack a physical presence, as one can move through them in Theater mode, they have scripted deaths, and they use very low-resolution textures applied to them. They are unaffected by the player's actions.

If one takes the camera in Theater mode outside the hangar, the Portal Storm can be seen forming.

After facing the Jump-pack Brutes, if one follow the hallway up to where they break out of, equipment and ammo can be found. One of them is Cloaking, which will be effective during the fight with War Chieftain on higher difficulties.

This is the only Halo 3 level where the player doesn't have a starting loadout weapon. Once gameplay begins, the player must pick own their loadout on weapon rack, allowing for a Magnum Pistol, Assault Rifle, SMG or Battle Rifle.